10.02 Superficial Finger Tip Avulsion

agk’s Library of Common Simple Emergencies

Presentation

The mechanisms of injury can be a knife, a meat slicer, a closing door, a falling manhole cover, spinning fan blades, or turning gears. Depending on the angle of the amputation, varying degrees of tissue loss will occur from the volar pad, or finger tip.

What to do:

• X ray any crush injury or an injury caused by a high speed mechanical instrument, such as an electric hedge trimmer.
• Consider tetanus prophylaxis.
• Perform a digital block to obtain complete anesthesia.
• Thoroughly debride and irrigate the wound.
• When active bleeding is present, provide a bloodless field by wrapping the finger from the tip proximally with a Penrose drain. Secure the proximal portion of this wrap with a hemostat and unwrap the tip of the finger.
• On a less than one square centimeter full-thickness tissue loss, apply a simple non-adherent dressing with some gentle compression.
• Where there is greater than one square centimeter of full-thickness skin loss there are three options that may be followed:
  • Simply apply the same non-adherent dressing used for a smaller wound.
  • If the avulsed piece of tissue is available and it is not severely crushed or contaminated, you can convert it into a modified full-thickness graft and suture it in place. Any adherent fat and as much cornified epithelium as possible must be cut and scraped away using a scalpel blade. This will produce a thinner, more pliable graft that will have much less tendency to lift off its underlying granulation bed as the cornified epithelium dries and contracts. Leaving long ends on the sutures will allow you to tie on a compressive pad of moistened cotton that will help prevent fluid accumulation under the graft. A simple finger tip compression dressing can serve the same purpose.
  • With a large area of tissue loss that has been thoroughly cleaned and debrided and where the avulsed portion has been lost or destroyed, consider a thin split-thickness skin graft on the site. Using buffered 1% xylocaine, raise an intradermal wheal on the volar aspect of the patient’s wrist or hypothenar emminence until it is the size of a quarter. Then, with a #10 scalpel blade, slice off a very thin graft from this site. Apply the graft in the same manner as the full thickness one (above) with a compression dressing.
• In infants and young children, fingertip amputations can be sutured back on in their entirety as a composite graft (ie, containing more than one type of tissue). In older children and adults, composite grafts will usually fail, and therefore is is important to “defat” the severed portion as noted above so that it is more likely to survive as a full-thickness skin graft.
• When the loss of soft tissue has been sufficient to expose bone, simple grafting will be unsuccessful and surgical consultation is required.
• Schedule a wound check in two to four days. During that time the patient should be instructed to keep his finger elevated to the level of his heart and maintained at rest.
• Apply a protective four-prong splint for comfort.
• Unless the bandage gets wet, a dressing change need not be done for seven to ten days. Even then, the innermost layers of gauze may be left in place if the wound appears to be clean and not infected. Always have the patient return immediately with increasing pain or other signs of infection.
• If the wound is contaminated, a 3-5 day course of an antibiotic like cephalexin 500 mg tid may be effective prophylais, but antibiotics are not routinely required for associated phalanx fracture.
• Prescribe an analgesic such as acetaminophen plus hydrocodone 7.5 mg or 10 mg.

What not to do:

• Do not apply a graft directly over bone or over a potentially devitalized or a contaminated bed.
• Do not attempt to stop wound bleeding by cautery or ligature, which are likely to increase tissue damage and probably unecessary. Do not forget to remove any constricting tourniquet used to obtain a bloodless field.

Discussion:

The finger tip, being the most distal portion of the hand, is the most susceptible to injury, and thus the most often injured part. Treating small and medium-sized finger tip amputations without grafting is becoming increasingly popular. Allowing repair by wound contracture may leave the patient with as good a result and possibly better sensation, without the discomfort or minor disfigurement of taking a split thickness graft. On the other hand, covering the site with a graft may give the patient a more useful and less sensitive fingertip within a shorter period of time. Unlike the full- thickness graft, a thin split-thickness graft will allow wound contracture and thereby allow for skin with normal sensitivity to be drawn over the end of the finger. The full- thickness graft, on the other hand, will give an early, tough cover which is insensitive but has a more normal appearance. The technique followed should be determined by the nature of the wound as well as the special occupational and emotional needs of the patient. Explain these options to the patient, who can help decide your course of action.

-----------------------------------------------------
from Buttaravoli & Stair: COMMON SIMPLE EMERGENCIES © 
Longwood Information LLC 4822 Quebec St NW Washington DC 20016-3229 
1.202.237.0971 fax 1.202.244.8393 electra@clark.net
-----------------------------------------------------